The present invention is applied to sports equipment where a device consisting of a long shaft, having a handle at one end and a head at the other end, is used to strike a play object, such as a ball, to make the ball to fly away at a great speed. In later discussions, the golf club is taken as a sample to illustrate the invention, but the application is not limited to golf clubs.
In golf, the driver is used to drive a golf ball to a large distance away, several hundred yards. The golf club consists of a handle, a long and slender shaft and a head which is a solid mass made of wood, metal and other materials. The head is used to strike the ball at a high speed, to propel it forward and when the ball is no longer in contact with the head, it will fly away at a large velocity. The distance it can travel depends on its initial speed, and the initial angle of inclination of the ball's trajectory with respect to the ground.
The head of the driver, more than 210 gm in weight, is much heavier than the shaft itself, about 100 gm. Handle is a portion of the shaft, usually comprising a grip made of frictional material, such as rubber, for the hand to hold. The purpose of having a heavy head is to have a large inertia mass to force the ball, 42 gm., to move quickly with minimum slowing-down of the head.